Black Hole Entropy in Scalar-Tensor and ƒ(R) Gravity: An Overview

Faraoni, Valerio

doi:10.3390/e12051246

Cited by 69 publications

(54 citation statements)

References 137 publications

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“…On the other hand, that the horizons we are concerned are of the bifurcate type means we are in Wald's hypothesis in order to compute their entropy. In this sense, equations (31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43) and Figure 1 represent our main results.…”

Section: Discussionmentioning

confidence: 70%

“…Some of the physical quantities one would like to address to dirty black holes are their mass, the horizon entropy, their temperature and so on. Thanks to the large amount of work carried over in the last decade, we can firmly say that the issue of entropy and temperature of dirty black holes represents a well posed problem [30]; a nice and recent review on the entropy issue associated with f (R) gravity models is [32], where a complete list of references can be found. Here, we only mention [22,23,33].…”

Section: Introductionmentioning

confidence: 99%

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Black Hole Entropy for Two Higher Derivative Theories of Gravity

Bellini

Criscienzo

Sebastiani

et al. 2010

Entropy

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The dark energy issue is attracting the attention of an increasing number of physicists all over the world. Among the possible alternatives to explain what as been named the "Mystery of the Millennium" are the so-called Modified Theories of Gravity. A crucial test for such models is represented by the existence and (if this is the case) the properties of their black hole solutions. Nowadays, to our knowledge, only two non-trivial, static, spherically symmetric, solutions with vanishing cosmological constant are known by Barrow & Clifton (2005) and Deser, Sarioglu & Tekin (2008). The aim of the paper is to discuss some features of such solutions, with emphasis on their thermodynamic properties such as entropy and temperature.

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Section: Discussionmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Black Hole Entropy for Two Higher Derivative Theories of Gravity

Bellini

Criscienzo

Sebastiani

et al. 2010

Entropy

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“…The proof is not valid in extended gravity theories, when the field equations differ from those of GR. This is the case of the Brans-Dicke theory (and, more generally, scalar-tensor gravity) [44,45], in which Einstein equations are modified by new terms beyond the energy-momentum tensor involving the scalar field.…”

Section: Test Of the Area Theoremmentioning

confidence: 99%

Hunting for Dark Particles with Gravitational Waves

Giudice

2017

EPJ Web Conf.

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Abstract. The LIGO observation of gravitational waves from a binary black hole merger has begun a new era in fundamental physics. If new dark sector particles, be they bosons or fermions, can coalesce into exotic compact objects (ECOs) of astronomical size, then the first evidence for such objects, and their underlying microphysical description, may arise in gravitational wave observations. In this work we study how the macroscopic properties of ECOs are related to their microscopic properties, such as dark particle mass and couplings. We then demonstrate the smoking gun exotic signatures that would provide observational evidence for ECOs, and hence new particles, in terrestrial gravitational wave observatories. Finally, we discuss how gravitational waves can test a core concept in general relativity: Hawking's area theorem.

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“…Several black holes have been got already for f (R) theories [6,[34][35][36][37][38][39][40][41][42][43][44]. And their physical properties are discussed in, e.g., [45][46][47][48].…”

Section: Introductionmentioning

confidence: 99%

Spherically symmetric black holes with electric and magnetic charge in extended gravity: physical properties, causal structure, and stability analysis in Einstein’s and Jordan’s frames

et al. 2020

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Novel static black hole solutions with electric and magnetic charges are derived for the class of modified gravities: f (R) = R + 2β √ R, with or without a cosmological constant. The new black holes behave asymptotically as flat or (A)dS space-times with a dynamical value of the Ricci scalar given by R = 1 r 2 and R = 8r 2 Λ+1 r 2 , respectively. They are characterized by three parameters, namely their mass and electric and magnetic charges, and constitute black hole solutions different from those in Einstein's general relativity. Their singularities are studied by obtaining the Kretschmann scalar and Ricci tensor, which shows a dependence on the parameter β that is not permitted to be zero. A conformal transformation is used to display the black holes in Einstein's frame and check if its physical behavior is changed w.r.t. the Jordan one. The thermal stability of the solutions is discussed by using thermodynamical quantities, in particular the entropy, the Hawking temperature, the quasi-local energy, and the Gibbs free energy. Also, the casual structure of the new black holes is studied, and a stability analysis is performed in both frames using the odd perturbations technique and the study of the geodesic deviation. It is concluded that, generically, there is coincidence of the physical properties of the novel black holes in both frames, although this turns not to be the case for the Hawking temperature.

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Black Hole Entropy in Scalar-Tensor and ƒ(R) Gravity: An Overview

Abstract: A short overview of black hole entropy in alternative gravitational theories is presented. Motivated by the recent attempts to explain the cosmic acceleration without dark energy, we focus on metric and Palatini f (R) gravity and on scalar-tensor theories.

Cited by 69 publications

References 137 publications

Black Hole Entropy for Two Higher Derivative Theories of Gravity

Black Hole Entropy for Two Higher Derivative Theories of Gravity

Hunting for Dark Particles with Gravitational Waves

Spherically symmetric black holes with electric and magnetic charge in extended gravity: physical properties, causal structure, and stability analysis in Einstein’s and Jordan’s frames

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